Comment 24 for bug 1828495
Revision history for this message
| Christian Ehrhardt (paelzer) wrote Re: [Bug 1828495] Re: [KVM][CLX] CPUID_7_0_EDX_ARCH_CAPABILITIES is not enabled in VM. | #24 |
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67d34a1
(Get the code!)
@rafael - One more question about Stepping 5/6.
I have formerly read your explanation that stepping 6 would be
required to be able to enable arch_capabilities.
And we planned to add all SRUs with stepping 6 right away and keep the
Delta to consider all versions to be stepping 6.
But then I have seen [1] and in particular [2].
Overall this adds more complexity but also more ability to CPU model
definitions.
But in between the lines in [2] I read that arch_capabilities gets
enabled by default and stepping goes back to 5.
That seems to imply that enabling it on stepping 5 isn't an issue.
If it does work doing the SRU that way it will ease maintenance in the future.
Especially since these versioned types will make maintaining Delta in
that area even more complex.
And it would avoid the upgrade issue on Disco where the CascadeLake
would change.
Therefore I wondered if we could make the backport use stepping 5
which would allow to not carry the delta forever in >=Eoan.
Could you make a PPA build as it is right now, but with stepping 5 and
check if using arch_capabilities still works for you?
[1]: https://<email address hidden>
[2]: https://<email address hidden>